Differential gas balance



Sept. 13, 1932.

A. B. CUNNINGHAM DIFFERENTIAL GAS BALANCE Filed April 25, 1924(fZZKEHZOT' 1 f entedtsepi. 13, 1932 turner.An CuNNINGHAM, or CHICAGO,ILLINOIS, ASSIGNOR T :enrunnrc FLOW .METERSCO OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS f @IEFERENLIAL GAS BALANCE lApplicationfilerlApril 23,

This invention relatestoa'device for measofgases by comparing theirrelative weight, andhasiforfits obj ecttheprovision of such a uring. thediiference in density of'two kinds device which shall beef improvedconstrucftion and operation and i in which stationary 'columns,ofthegases are compared,;there being means for replenishing the gas in onejgof the columnsrepeatedlyjto providea sub- Fig. 2 is ahorizontalsectionsubstantially stantia'lly continuous indication of thecharacteristics of the gas from which the supply is taken; Theinventionis exemplified in the I combination and arrangement of partsshown in the accompanying drawing 3 and described in the followingspecification and itis more particularly pointed, out in the appendedclaims. ,Inthe drawing 7' a Figure 1 is a vertical sectional view withparts in' elevation showing onetembodiment of the present invention;

on line 2+2of Fig. 1;

= 1 Fig. 3 is aside elevation oflthe top portion o f'the samplecolumn;and v t i Fig. 4 18a fragmentary top plan view of a i the supportfor'the balance beam. q Theembodiment of the invention illustrat ed inthe draw ing is arranged to determine the relative weight "of acolumn ofgas as comparedwith thelweightiofajcolumn of air. of thesameheighhtheresult being indicated electrically: The apparatus may beused forindicating; continuously the specific gravity of the gas taken from anygiven source or for indicating. the percentage of various constituentsof the gaslsuchffor instance, as the percentage-of carbon dioxid influe. gases or the percentage of sulphur jidioxid'ina given mixturewOther uses of the invention will I readily*sug'gest themselves to thoseskilled inthe art; I

Referring more particularly the drawling, 1the"numeral 1L0 designates,ajlarge tank made of {suitable materiah*jthefl tank being 5;loosely'closed 'at 'thetop sothat "the interior 1924. Serial No. voasss.

sure. Inside the tank there is a large bell 11 sealed by a liquid 12which may be oil or other suitable substance. The bell 11 is of lightconstruction and is supported by a rod 18 suspended from a knife edge 14carried on a balance beam 15. The beam 15 is supported by a knife edge16 which rests on a pair of fixed beams 17 secured at their oppositeends to the walls of the tank 10. One end of the beam 15carries ahousing 18 for containing an electrical resistance member having aseries of contact rods 19 tapped therefrom at difierent positions andextending downwardly toward a conducting fluid 20 held in a receptacle21. The contact rods 19 are of diiferent lengths so that varying amountsof the resistance in thecontainer 18 will be short edge 23 mounted onthe beam 15. One end of the resistance member in the housing 18 isgrounded on the tank 10 and hence makes contact with a conductor 24electrically connected with the tank. The opposite end of the resistancemember is connected through the contact rods 19 and the liquid 20 with abracket 25 insulated from the tank 10 and connected with a conductor 26.As the height of the container 18 is changed by a movement of the beam15 the resistance in the circuit between the conductors 24 and 26 willbe varied. If the conductors are connected to a suitable source ofcurrent such as a battery 27 and an indicating instrument such as anammeter 28, the instrument will indicate the amount of current flowingin the circuit which in turn will give an indication of the position ofthe beam 15. This method of indicating electrically the position of amovable member is more fully described in atent to Jacob M. SpitglassNo. 1,890,394l. bince'the "beam15 is 'controlledby'the bell 11, theammeter 28 will indicate the height of the bell 11. A counterbalancingweight 29 is secured to the end of the beam opposite the housing 34having an inlet 35 and an outlet 36 con-- necting the pump with thedistributor. The pump 34 is provided with a drive pulley 37 which may beconnected with any suitable source of power. The pump shaft 38 isconnected by w'orm'gear-39 with 'a vertical shaft 40 passing through thedistributor 33 and provided with a revolving vane or di'viding member41. The shaft .40 is concentric with the cylindrical wall of thedistributor 33 so that --thejvane 41 divides the interior-of the .pairofisamplecolumns 42 and 43 communicate with the-distributor 33 throughopenings 44 and 45, respectively. v It will be noted that theopenings 44and 45'are offset slightly relatively in the same direction to thecenter of p the distributor so that during rotation of the vane 41 oneof the openings -44and 45 willbe connectedfwith the pipe 36 leading tothe pump 34 slightly before the other; opening is disco'nnectedtherefrom. In this way the pipe "3 6 is at no time connected to acomletel closed chamber as sucha condition P y a would produce anundesirable back pressure l onthe pump. The upper ends of the sample.columns42 and 43 are connected to a common compartment 44 which isopen-atits top to .1 the atmosphere. The rotation of the vane41alternately connects the columns 42 and43 with the pipes 36 and 32respectively, sothat fora short periodjoneof the sample columns willbesupplied withgas from the 'pump34 andwill thenbe disconnected from thepum and connected with the bell 1'1 throughthe; pipe 32. While thecolumn is connected with thebell it willbe disconnected from the pumpsothat the pressure exertedion the interiorof the bell will be producedby a stationary col- 7 j umn of gas in the vertical tube which is free ifrom any movement produced by the pump.

3 While one of the sample columns 42 and 43. is 7 connected with thebell ll'the other will be in communication with the pump in order to bev supplied with a fresh charge from the source of supply. At no timeisthe outlet 32 and j'the interior-ofthe bell 11 subjected to the{pressure exerted by the pump. By this arrangement the interiorof thebell 11 is continuously subjected to pressure exerted by a source ofsupply at all times;

Gas is supplied to P son. I ,7 V

c It will be noted that for a short distance. at their tops the twocolumns are united'in a single chamber. 4 This ensures a supply of Inoperation the usual intervals for inter change between the columns isabout five seconds, which permits the entire contents of the column tobe changed by the fresh supply. Since the exterior of the bell 11 issubjected to atmosphere it will be apparent that the difference inpressure between the exterior and interior of the bell will be a measureof the difference in weight between the column of gas in the sample tube42 or 43 connected with the interior of the bell and a column of air ofthe same height. The tubes 42 and 4 3 are much less in cross sectionalarea than the interior of the bell but the pressure produced within thebell is 0f course inde- I equal-to the height of the sample tubes 42distributor .into equal "compartments. A

and 43 andcross sectional areas equalto the area of-th'e bell 11. Thisdifference ofweight between two gases is of course arelatively smallquantity,-and when a columnofgas of ten or even twenty feet is usedthedifference ofpressure will be onlya few hundredths of an inch of waterpressure. It isfound that I if the gas in the sample column is movingattempt is made touse a 'movingcolumn of gas the error sometimes amountstoover one hundred per cent. The present invention' prevents thisdifiiculty, since; a'stationary column ofgas isalwaysused for making acomparigas at the top-of the column, at all times so thataifr isexcluded fromthe top of the-column, thus'ensuring'a complete column ofgas 1 even thoughthe pressure in the bell should raise the bell so as tolower the gas in the column. r

i, While I have describedone embodiment of the nvention and havereferred to some {uses to whlch the invention may be put, it will-beunderstood that many variationsin details may be madewithout departing.from the spirlt of theinventionas defined in; the 'appended claims, andthat many-other uses will readily suggest themselves to those skilled in-the art.

IE-Iclaimz I. f

' 1." A idiflerential :gas 'bala'nce, comprising -a' bell; means forsubjecting said bell to dif ferential gas balance beam, a plufralit ofeontactmembers of different lengths carriedby said beam, a conductor forengaging the ends of different contact members for difierent positionsof said beam, and electrical indicating means connected with said con- 3f ductor and contact members.

2.- Gas testing apparatus, comprising [a bell, a pair of stand pipes forreceiving gas to be tested,a source ofsupply, a distributor connectedwith jsaidsourceof supply, stand pipes and bell, said distributor havingmeans y for alternately and separately connecting each of saidstandpipes successively with said source ofsupplyand said bell and acommon chamberconnected with said standpipes atthe top thereof. :f' V 3;Gasitestin'g apparatus, comprising a pressure indicatorfa pair of standpipes connected attheir tops to a common chamber open to atmosphere, asource of gas supply, and ajdistributor having means for periodicallyconnecting each ofsaid stand pipes separatelyj andsuccessively with saidsource of supply and with said indicator,-each pipe I being disconnectedfrom said source of supply stand pipes, separately with said source of iwhile connected withsaid indicator.

i 4. Gastesting apparatus, comprising an indicator, a pairof standpipes, a source of supply, means for alternately connecting said supplyandsaid indicator, and a common a I as having a fluid therein,aninverted bell sealed chamber connected with the tops of said stand pipesand open to atmosphere.

5. Gas testing apparatus, comprising a tank by said fluidfabalance beamfor supporting said bell, an electric circuit, means actuated i by saidbeam for controlling said circuit,

40 :atmosphericpressure, a stand pipe, a source,

I of supply, and means foralternately connectthe exterior'of said bellbeing subjected to ing said stand pipe with said source of supply andthe interior of said bell and for disconnecting said stand pipe fromsaid source of supply while connected with said bell to sub- 1 ject theinterior of saidbell to the pressure of a stationary column ofgas insaidstand P Pe W a a 6. Gas testing apparatus, comprising a tank, aninverted bell within U said tank,

i tact members actuated by said beam forconliquid within said tank forsealing said bell, the exterior of said bell beingsubjected toatmospheric pressure, a balance beam for supporting said bell, anelectric circuit, controlling said electric circuit, apair'of standpipes having a commonchamber at their a tops open tolatmosphere, asource of gas supply, a distributor connected with said source of supplyand withsaid stand pipes and withtheinteriorjof said bell, and a itdividingTdevice movably arranged within saiddistributor and adapted tod;

each of said standpipesseparately and alternately withsaidsource ofsupply and the interior of saidfbelland to disconnect each stand pipefrom the source of supply while it is connected with said. bell and todisconnect eachstand pipe from said bell while it is connectedwith saidsource of supply.

, 7. Gas testing-apparatus, comprislnga pump,'a pair of stand pipes,anda cylindrical distributor,,'said distributor having a rotary dividertherein concentrically arranged therewith and extending across saiddistributor, said pipes being connected with said distributor on theside of a given diameter adjacent the connection with said pump so thatsaid pump will be connected at all times with one or the other of saidstand pipes.

8. Gas testing apparatus comprising in combination, a liquid sealed bellmounted for movement responsive to gas pressure within said bell, astand pipe having a conduit connection with said bell, a pump fordelivering gas to said stand pipe, an indicating instrument, an electriccircuit for said v i instrument, and means for introducing resistanceinto said circuit in proportion to the movement of said bell.

9. Gas testing apparatus comprising in combination, a liquid sealed bellmounted for movement responsive to gas pressure within said bell, a pairof stand pipes connected at their top portions and open to theatmosphere, a distributor connecting the.

bottom of said pipes,v a conduit connecting said distributor with saidbell, a pump consaid openings being arranged with respectto said valveso that one of said openings is thrown into communication with saidsource of supply beforethe other of said openings is .cut off fromcommunication with said source of supply.

11. A gas testing apparatus comprising a chamber, a valve rotatable insaid chamber, stand pipes opening into said chamber on opposite sidesthereof, an inlet pipe from a source of supply opening into saidchamber, means for moving said valve to alternately connect said standpipes with said source of supply, said ,valve being so located withrespect to said stand pipes as to cause one of said stand pipes to beconnected with said source of supply before communication-isdiscontinuedbetween the other of said stand pipes and the sourceofsupply.

12. A gas-testing; apparatus comprising a 5 distributor. chamber, aninlet tosaid chamber, outlets from said ohamberland means .7 forconnecting said inlet with one of said outlets before disconnecting saidother outlet from said inlet.

)10 In testimony whereof I have signed :my

name to this specification on this 31st day of March, A. D. 1924.

ARTHUR B; CUNNINGHAM.

